Damaging Winds in South Carolina, August 22 to 23, 2007

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
251 PM EDT WED AUG 22 2007

.SYNOPSIS...
STRONG UPPER LEVEL HIGH PRESSURE HAS BEGUN TO RETROGRADE TO THE
WEST. THIS WILL WEAK WEATHER DISTURBANCES TO MOVE SOUTHEAST FROM
ACROSS SOUTH CAROLINA AND EASTERN GEORGIA THIS EVENING AND
TOMORROW. THIS WILL INCREASE CHANCES OF THUNDERSTORMS AND BRING
SOMEWHAT COOLER WEATHER TO THE AREA. HEAT ADVISORY WILL BE ALLOWED
TO EXPIRE.

&&

.NEAR TERM /THROUGH TONIGHT/...
WEAK SURFACE TROUGH STRETCHED ACROSS PORTIONS OF THE CENTRAL AND
SOUTHERN FORECAST AREA. WATER VAPOR IMAGERY INDICATING AN UPPER
DISTURBANCE ACROSS CENTRAL NC...MOVING SE. MODELS SUGGESTING
ANOTHER UPPER IMPULSE TO AFFECT THE VICINITY TONIGHT AND THURSDAY.
MEANWHILE...BACK DOOR FRONT ACROSS NE NC TO SHIFT SW...AND MAY
MOVE FAR ENOUGH TO THE SW TO AFFECT NE/E PORTIONS OF OUR FA
THURSDAY. HOT TEMPERATURES THIS AFTERNOON WILL PROVIDE FUEL FOR
SCATTERED THUNDERSTORMS AS A COMBINATION OF SURFACE BOUNDARIES AND
UPPER IMPULSES INTERACT WITH THE WARM AIR. THE LATEST LAPS AND FORECAST
SOUNDINGS INDICATE REALTIVELY HIGH LFCS AND CONVECTIVE
TEMPERATURES...WHICH MAY REDUCE COVERAGE THIS EVENING...BUT WHAT DOES
DEVELOP WILL HAVE THE POTENTIAL TO BE STRONG WITH MODERATE TO
STRONG INSTABILITIES. WILL RAISE POPS THIS AFTERNOON TO 30
THROUGHOUT THE FA. WILL UPDATE HWO TO ADDRESS ISOLATED SEVERE
THUNDERSTORM POSSIBLE. THE PRESENCE OF THE BACK DOOR COLD FRONT
AND ADDITIONAL MID LEVEL WEATHER DISTURBANCES MOVING OVER HEAD
FROM THE NORTHWEST WILL PROLONG THE CHANCE OF PRECIPITATION OVERNIGHT.

&&

.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
FAVORED NAM MODEL SOLUTION OVER GFS...WITH CONVECTIVE FEED BACK
BEING THE MAIN PROBLEM. POPS WERE RAISED TO 30 ACROSS THE ENTIRE
AREA AS THE PRESENCE OF MULTIPLE OUTFLOW BOUNDARIES AND CONTINUES
PRESENCE OF VERY WARM ATMOSPHERE WILL CONTINUE TO GIVE THE AREA
CHANCES OF THUNDERSTORMS. THE CHANCE OF THUNDER DECREASES
OVERNIGHT THURSDAY AS A SHORT WAVE RIDGE ROTATING AROUND THE HIGH
TO OUR WEST MOVES DOWN OVER THE AREA. CURRENT FORECAS OF A SLIGHT
CHANCE OF PRECIPITATION WAS RETAINED.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
MODEL GUIDANCE CONTINUES TO ADVERTISE THE RETROGRADATION OF UPPER
RIDGE TO THE WEST. THIS WILL ALLOW THE DEVELOPMENT OF A LONG WAVE
TROUGH OVER THE EASTERN UNITED STATES. THIS WEATHER PATTERN SHIFT
WILL ALLOW COOLER AIR TO MOVE SOUTHEAST ACROSS THE FORECAST AREA.
HIGHS WILL ONLY BE IN THE LOWER 90S VS THE 100S WE HAVE SEEN OVER
THE PAST WEEK. THE UPPER TROUGH WILL ALLOW FOR WEAK WEATHER
DISTURBANCES TO CROSS THE AREA FROM THE NORTHWEST. AS A RESULT
THERE WILL CONTINUE TO BE CHANCES OF THUNDERTORMS THROUGHOUT THE
PERIOD.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
LATEST RADAR INDICATING SOMWE SHOWERS AND THUNDERSTORMS
DEVELOPING. AT THIS TIME...WILL HANDLE PRECIPITATION POTENTIAL
WITH VCSH...AND AMEND IF/WHEN HIGHER CONFIDENCE OF TS AFFECTING
TAF SITES WARRANTS. WILL NOT MENTION RESTRICTIONS TO VSBY LATE
TONIGHT/THURSDAY MORNING AT THIS TIME DUE TO UNCERTAINTIES WITH
REGARD TO WIND AND CLOUD COVER.

AVIATION OUTLOOK...PERIODS OF MVFR TO IFR FOG POSSIBLE DURING THE
LATE NIGHT/EARLY MORNING HOURS. THERE WILL BE A SLIGHT CHANCE OF
MAINLY AFTERNOON AND EVENING THUNDERSTORMS. OTHERWISE...NO
SIGNIFICANT IMPACTS EXPECTED THURSDAY THROUGH MONDAY.

&&

.CLIMATE...
YESTERDAY MARKED THE 13TH TIME THE HIGH TEMPERATURE WAS 100 OR
HIGHER IN COLUMBIA THIS MONTH. THIS BROKE THE AUGUST RECORD OF 12
SET IN 1900. THE ALL TIME MONTHLY RECORD IS 17 DAYS SET IN JULY
1993.

YESTERDAY WAS THE 14TH TIME THE TEMPERATURE WAS 100 OR HIGHER IN
AUGUSTA DURING AUGUST. THIS IS A RECORD FOR THE MONTH. THE ALL
TIME MONTHLY RECORD IS 17 DAYS SET IN JULY 1993.

TODAY/S HIGH TEMPERATURES ARE EXPECTED TO REMAIN BELOW THE RECORD
FOR THE DAY. THE RECORD HIGH FOR COLUMBIA FOR AUGUST 22ND IS 106 SET
IN 1983. THE RECORD HIGH FOR AUGUSTA FOR THE DATE IS 107 ALSO SET
IN 1983.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR SCZ015-016-018-
     020>022-025>031-035>038-041.
GA...HEAT ADVISORY UNTIL 7 PM EDT THIS EVENING FOR GAZ040-063>065-
     077.

&&

SYNOPSIS...12
NEAR TERM...12
SHORT TERM...12
LONG TERM...12
AVIATION...07

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE COLUMBIA SC
159 PM EDT WED AUG 22 2007

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-231800-
LINCOLN-MCDUFFIE-COLUMBIA-RICHMOND-BURKE-LANCASTER-CHESTERFIELD-
MCCORMICK-NEWBERRY-FAIRFIELD-KERSHAW-EDGEFIELD-SALUDA-LEXINGTON-
RICHLAND-LEE-AIKEN-SUMTER-BARNWELL-ORANGEBURG-CALHOUN-CLARENDON-
BAMBERG-
159 PM EDT WED AUG 22 2007

...HEAT ADVISORY IN EFFECT UNTIL 7 PM EDT THIS EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL GEORGIA AND
CENTRAL SOUTH CAROLINA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   HEAT ADVISORY.

HEAT INDEX VALUES 105 TO 109 DEGREES THIS AFTERNOON.

EXPECT A CHANCE OF SHOWERS AND THUNDERSTORMS. AN ISOLATED
THUNDERSTORM MAY BECOME SEVERE LATER THIS AFTERNOON AND EVENING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.